In a crusher of the type to which this invention relates, a generally conical crushing head is mounted on an upright eccentric shaft to be gyrated by rotation of the eccentric. On the relatively stationary frame of the crusher there is an annular crushing bowl or concave that surrounds the crushing head and cooperates with it to define a gap which comprises an annular crushing chamber. Material to be crushed is fed downward between the bowl and the head, to be crushed by the gyration of the head.
The particle size of the output of such a crusher is dependent upon the size of the gap between the bowl and the crushing head. So that product particle size can be adjusted and compensation can be made for wear on the opposed surfaces of the crushing head and the bowl, it is customary to mount the bowl for up and down adjustment relative to the crusher frame whereby the crushing gap is widened by raising the bowl or narrowed by lowering it. For such adjustment, the bowl has a helically threaded connection with an upper frame member, and the bowl is shifted up or down by rotating it in the appropriate direction relative to the frame.
Once satisfactorily adjusted, the bowl must be prevented from rotating relative to the frame in response to the tangential forces imposed upon it by the gyrating crushing head. In many cases the bowl is releasably locked against rotation by a clamping ring just above the bowl that also has a helically threaded connection with the frame and functions in the same manner as a conventional lock nut or jam nut. Since the arrangement of the elements is such that adjusting rotation must be imparted to the bowl through the clamping ring, they are connected to rotate in unison but to be free for limited axial motion relative to one another. To lock the bowl against rotation, a substantial force is exerted between the bowl and the clamping ring whereby they are urged axially towards one another. For adjusting rotation of the bowl, this clamping force must of course be released.
Various arrangements have been proposed for providing the necessary clamping force between the bowl and the clamping ring, but heretofore there has been no satisfactorily simple and inexpensive arrangement that provides for both locking and unlocking of the bowl in a quick and facile manner.
U.S. Pat. No. 2,881,981 disclosed an arrangement wherein the rotation transmitting connection between the bowl and the clamping ring comprised an annular series of bolts or studs that were threaded into the bowl and projected upwardly from it through substantially closely fitting holes in the clamping ring. The upper end portion of each bolt was slotted to receive a wedge that overlay an upwardly facing surface on a part connected with the clamping ring and imposed a downward force upon the clamping ring while exerting an upward force upon the bowl through the bolt. Since there were a substantial number of bolts around the crusher, it was a tedious and laborious task to drive a wedge into each bolt slot in order to lock the bowl after an adjustment, and equally time consuming and troublesome to remove all of the wedges in order to unlock the bowl for adjustment. Arrangements generally similar to that of U.S. Pat. No. 2,881,981 are disclosed in the substantially later U.S. Pat. No. 3,533,568 and U.S. Pat. No. 3,614,023.
In the crushers of several other prior patents, as in that of the present invention in its preferred form, the bowl and the clamping ring were again connected for rotation by means of circumferentially spaced bolts secured in the bowl and projecting up from it through the clamping ring.
U.S. Pat. No. 3,204,883 disclosed an arrangement wherein a number of upright hydraulic jacks, arranged in a circle, reacted between parts that were respectively secured to the clamping ring and to the ring of bolts projecting up from the bowl. Pressure fluid was supplied to the several jacks for initial locking of the bowl, and thereafter the bowl was held in locked condition by mechanical locking means comprising wedges or locking pins, to permit hydraulic fluid pressure to be relieved without unlocking of the bowl.
U.S. Pat. No. 3,459,383 disclosed a toggle linkage for each of the bolts, each toggle linkage being actuatable to its overcenter clamping position to exert an upward force upon its bolt, and hence on the bowl, while exerting a downward reaction force upon the clamping ring. A double-acting hydraulic jack for each toggle linkage, extendable and retractable transversely to the links and connected to the swivel joint between them, moved the toggle to its clamping position and to its releasing position. Because of the overcenter arrangement of the toggle linkage, it could maintain its force-applying condition and lock the bowl even though fluid pressure on its actuator was subsequently relieved. Although quick acting and easy to operate, the arrangement was mechanically complex and quite expensive, because there had to be a substantial number of toggle linkages, each comprising several parts, and an equal number of hydraulic jacks.
U.S. Pat. No. 3,341,138 disclosed an arrangement wherein an upper portion of each bolt that connected the bowl and the clamping ring was surrounded by a compression spring that reacted downwardly against the clamping ring and upwardly against a nut on the top of the bolt. For releasing the axially convergent locking force thus exerted by each spring, a hydraulic jack was mounted above each bolt, on a cap that was fixed to the clamping ring and projected above it. When fluid pressure was applied to the jack, it extended to exert downward force on the top of its bolt, and thus upon the bowl, while imposing its upward reaction force upon the clamping ring through the cap. Upon relief of hydraulic pressure on the jacks, the springs could take over and urge the bowl and the clamping ring toward one another into locking relationship with the threaded frame portion. Although less complicated and costly than the arrangement of U.S. Pat. No. 3,459,383, and at least as satisfactory from a functional standpoint, the mechanism of U.S. Pat. No. 3,341,138 nevertheless required a number of hydraulic jacks and the numerous parts and fittings comprising their hydraulic systems.
By contrast to these prior art expedients, the present invention has as its general object the provision of an extremely fast-acting, simple and effective arrangement for locking the bowl of a gyratory crusher against rotation relative to the frame member that carries it and for unlocking it to be adjustingly rotated relative to that frame member, all without need for any cylinder jack or the like.
More specifically, the general object of the present invention is to provide a gyratory crusher having a bowl which is adjustable up and down by rotation and which is normally locked against such rotation by means of a clamping ring that is connected with the bowl to rotate in unison with it, in cooperation with spring means reacting between the bowl and the clamping ring to bias them towards one another, and having very simple means for overcoming the force of said spring means at times when the bowl is to be adjusted up or down, to thus permit the bowl and the clamping ring to be rotated relative to a frame member with which both have helically threaded connections.
Another object of the invention is to provide a bowl unlocking arrangement of the character described wherein fluid pressure is employed for bowl unlocking but wherein there are no hydraulic cylinders or the like and wherein the bowl is automatically locked against rotation as soon as fluid pressure is relieved.
A further object of the invention is to provide a gyratory crusher of the character described wherein the force that is employed to unlock the bowl or concave for up and down adjusting rotation is obtained from pressurized air, so that no contamination or fire hazard can result from any leak that might develop in the bowl unlocking system.
It is also a specific object of this invention to provide a pneumatic bowl unlocking arrangement wherein pressure air is applied directly to the bowl and the clamping ring, avoiding the cost and complexity of cylinder jacks and the like.